Apparatus for continuous chemical reactions



Nov. 27, 1962 F. 1'. E. PALMQVIST 3,066,015

APPARATUS FOR commons CHEMICAL REACTIONS Filed March 1. 1960 lA/VE/VTUR Fedr-ik 75. Palm VI'S? United States Patent Ofitice Patented Nov. 27, 19%;?

3,066,015 APPARATUS FGR CONTINUOUS CHEMICAL REACTIONS Fredrik T. E. Palmqvist, Solna, Sweden, assignor to Aktiebolaget Separator, Stockholm, Sweden, a corporation of Sweden Filed Mar. 1, 1960, Ser. No. 12,051 Claims priority, application Sweden Mar. 9, 1959 2 Claims. (Cl. 23-285) The present invention relates to chemical apparatus and more particularly to an improved reaction circuit for continuous-flow processing.

An apparatus having a flow circuit with spaced inlets for respective reaction components, and a single outlet for the reaction mass, is utilized for the manufacture of soap by saponification of fat with alkali lye. Similar apparatus, used in the sulphonation of organic compounds, has a circuit including a feed screw followed by a chamber provided with a stirring device. The chemicals to be reacted are fed into one end of the chamber by the feed screw. Apparatus of both these types are unsuitable if the reaction mass obtained is very viscous or if it is necessary to supply, or lead off, substantial amounts of heat during the reaction.

The apparatus of this invention has a reaction circuit provided with at least two separated inlets for the respective chemicals to be reacted, and an outlet for the reaction mass located (reckoned in the direction of fluid flow) beyond the inlet points, one of the inlets opening into a reaction chamber forming part of the circuit. A pump feeds the materials through the fluid reaction circuit, and a stirring device having a rotating shaft with attached vanes sweeps the inside surface of the reaction chamber.

An example of a reaction for which the apparatus of this invention is suitable is saponification of fat with lye (from about 42% concentration up to saturated lye). The concentration of the saturated lye increases with the temperature. In this saponification process, a highly viscous soap of low aqueous content is obtained. When this reaction was carried out in prior devices, the various reaction chemicals were insuflicicntly mixed with the soap mass circulating through the fluid circuit. Also, in such prior devices the viscosity of the soap mass made it diflicult to supply the necessary heat to the fluid circuit, as the viscous soap mass formed a heat-insulating layer along the inside wall of the apparatus.

Another example ofa reaction which may oe carried out to advantage in the apparatus of the invention is the neutralization of sulphonic acid with alkali lye (sulphonation). Even if the concentration of lye is less than 40%, a very viscous sulphonate mass is obtained. The apparatus heretofore used in soap manufacture, if used in this neutralization process, would not provide the necessary cooling, so that the resulting sulphonate mass would be overheated and dark-colored. The apparatus heretofore used in sulphonation, where lye and sulphonic .acid are fed to the circuit at the same point (at one end of a feed screw), likewise results in a dark-colored sulphonate mass, due to overheating.

Other features of the invention are apparent from the following detailed description in reference to the accompanying drawing, in which the drawing is a side view, partially cut away, illustrating the apparatus of the invention, including its fluid circuit.

In the drawing, pipeline 2 joins the upper and lower parts of reaction chamber 1 to form a fluid circuit. The inserted arrows show the flow direction. In pipeline 2 is a pump 3 which effects the circulation of the reaction mass through the circuit and its discharge from chamber 1. In reaction chamber 1, having a cylindrical inside wall, is screw conveyor 6 driven by rotating shaft 7. The screw conveyor is an enclosed helix formed about the axis of driving shaft 7. The driving motor for shaft 7 is not shown. Screw conveyor 6 keeps the formed mass scraped away from the inside of reaction chamber 1 and aids the pump 3 in feeding the material through the fluid circuit. One of the chemicals to be reacted is pumped into chamber 1 by way of inlet pipe 4 and pipe line 2, and the other is pumped directly into chamber 1 through inlet pipe 5. The reacted product is discharged through outlet pipe 10 leading from chamber 1. Pipe line 2 is in effect a return duct connecting opposite end portions of reaction chamber 1.

Preferably, screw conveyor 6 comprises relatively sparsely arranged threads 8 and more closely arranged threads 9. The stirring effect of screw 6 is improved by threads 8 and 9 being low pitched, or by screw 6 having a plurality of threads running in parallel, or by screw 6 having partly left-hand threads and partly right-hand threads. it partly left-hand and partly right-hand threads are used, one of these thread types predominates over the other so that the screw in its total eflect conveys the reaction mass towards one of its ends. Screw threads 9, in the area where one of the reaction components is fed (next to inlet pipe 5), are designed to produce an extra vigorous stirring effect in the reaction chamber.

In operation, in the reaction between alkali lye and sulphonic acid, pump 3 and the motor for shaft 7 are started. Cooling fluid is pumped through a cooling jacket (not shown) surrounding chamber 1. Lye is pumped into the fluid circuit through inlet pipe 4,, and sulphonic acid is simultaneously pumped into chamber 1 through inlet pipe 5. The lye and acid react to produce heat and a sulphonate mass. This mass is conveyed toward outlet pipe in by rotation of screw conveyor 6. Threads 9 convey the sulphonate mass and impart to the mass an extra vigorous stirring in the area (near inlet 5) where the sulphonic acid is fed. This vigorous stirring is especially important at the instant when the sulphonic acid meets the circulating sulphonate mass which contains lye. At that instant, large quantities of heat are developed. In order that the sulphonate mass should not be burnt or dark-colored through local overheating, a rapid distribution of the sulphonic acid in the sulphonate mass and a rapid leadingoff of the developed reaction heat through the walls of the reaction chamber must take place. Scraping of the walls so that the cooling fluid cools all parts of the mass, with simultaneous stirring, prevents local overheating. The resulting sulphonate mass is then discharged from the fluid circuit through pipe 10, which is connected to the upper part of the reaction chamber.

The new apparatus is suited for manufacturing soap with the use of fatty acids as starting material, and for carrying out other chemical processes in which viscous reaction masses are formed and large amounts of heat are developed, such as sulphonation and sulphatation processes.

Modifications may be made in the above-described apparatus within the scope of the invention and the subjoined claims.

I claim:

1. Apparatus for continuously eflecting chemical reactions, which comprises a fluid circuit having two inlets arranged at different points of the circuit for admitting thereto respective chemicals to be reacted, the circuit also having an outlet located beyond said inlets for discharge of the reaction mass, a pump in said circuit for feeding the reaction mass through the circuit, the circuit including a reaction chamber having opposite end portions, one of said inlets opening into the reaction chamc.) her at a point intermediate said end portions thereof, and a conveyor screw rotatably mounted in the reaction chamber in position to scrape the chamber walls, said screw having threads disposed from one to the other of said end portions and arranged in the region of said one inlet to efiect a more vigorous stirring action in said region than elsewhere in the chamber, said circuit including a return duct connecting said opposite end portions of the reaction chamber.

2. Apparatus for continuously effecting chemical reactions, which comprises a fluid circuit having two inlets arranged at different points of the circuit for admitting thereto respective chemicals to be reacted, the circuit aiso having an outlet located beyond said inlets for discharge of the reaction mass, a pump in said circuit for feeding the reaction mass through the circuit, the circuit including a reaction chamber having opposite end portions, one of said inlets opening into the reaction cham- A bet at a point intermediate said end portions thereof, and a conveyor screw rotatably mounted in the reaction chamber in position to scrape the chamber walls, said screw having threads disposed from one to the other of said end portions and spaced closer together in the region of said one inlet than are the threads elsewhere on the screw, to effect a more vigorous stirring action in said region than elsewhere in the chamber, said circuit including a return duct connectim said opposite end portions of the reaction chamber.

References Qited in'the file of this patent UNITED STATES PATENTS 2,931,822 Tischbirch Apr. 5, 1960 

1. APPARATUS FOR CONTINOUSLY EFFECTING CHEMICAL REACTIONS, WHICH COMPRISES A FLUID CIRCUIT HAVING TWO INLETS ARRANGED AT DIFFERENT POINTS OF THE CIRCUIT FOR ADMITTING THERETO RESPECTIVE CHEMICALS TO BE REACTED, THE CIRCUIT ALSO HAVING AN OUTLET LOCATED BEYOND SAID INLET FOR DISCHARGE OF THE REACTION MASS, A PUMP IN SAID CIRCUIT FOR FEEDING THE REACTION MASS THROUGH THE CIRCUIT, THE CIRCUIT INCLUDING A REACTION CHAMBER HAVING OPPOSED END PORTIONS, ONE IF SAID INLET OPENING INTO THE REACTION CHAMBER AT A POINT INTERMEDIATE SAID END PORTION THEREOF, AND A CONVEYOR SCREW ROTATABLY MOUNTED IN THE REACTION CHAMBER POSITION TO SCRAPE THE CHAMBER WALLS, SAID SCREW HAVING THREADS DISPOSED FRIM ONE TO THE OTHER OF SAID END PORTIONS AND ARRNAGED IN THE REGION OF SAID ONE INLET TO EFFECT A MORE VIGOROUS STIRRING ACTION IN SAID REGION THAN ELSEWHERE IN THE CHAMBER, SAID CIRCUIT INCLUDING A RETURN DUCT CONNECTING SAID OPPOSISTE END PORTIONS OF THE REACTION CHAMBER. 